The present invention relates to a concetration valve for a gas detecting apparatus, or the like, in a system for determining the presence a particular gaseous material or materials in a sample gas, such as air.
More specifically, the invention contemplates a concentration valve having adsorbing means operable to adsorb at least one gaseous material or vapor from a sample gas in a sampling position, and having means operable in an analyzing position for heating the adsorbing means to desorb into a carrier gas any gaseous material or vapor adsorbed from the sample gas. The carrier gas with the desorbed gaseous material or vapor therein is delivered to a suitable analyzing apparatus, e.g., a gas chromatograph.
As general background relating to the detection of a particular gaseous material or vapor from a sample gas, attention is directed to Dravnieks et al U.S. Pat. No. 3,430,482. Prior art specifically disclosing earlier concentration valves for use with apparatuses for detecting gaseous or vaporous materials in sample gases includes my U.S. Pat. Nos. 3,675,466 and 3,733,908, and Showalter et al U.S. Pat. No. 3,925,022. These patents also provide general background information respecting the field of detecting gaseous materials or vapors in sample gases, such as air. Consequently, a further discussion of the general field herein is unnecessary.